1. Field of the Invention:
The present invention relates to a process for the catalytic oxidation of alkanes, and, more especially, for the catalytic oxidation of alkanes into mixtures of alcohols and ketones.
2. Description of the Prior Art:
The catalytic oxidation of alkanes by organic hydroperoxides is a reaction known to this art and various catalytic systems have already been proposed for conducting such reaction.
Thus, D. Mansuy et al, in Angew. Chem. Int. English Edition, 19. No. 11, pages 909-910 (1980), described the decomposition of cumyl hydroperoxide in cyclohexane at 20.degree. C., in which the catalyst was the Os(TPP)(CO)(pyridine) complex wherein TPP designates tetraphenylporphyrin. However, the yield of desired compounds (cyclohexanol and cyclohexanone) was insignificant and the activity of the catalyst was very low. Moreover, if its structure is modified at 20.degree. C., experiments have shown that it is destroyed at a higher temperature. Under these conditions, development of such a technique on an industrial scale using a complex of prohibitive cost is not realistic.
Also, published French Patent Application No. 2,559,154 describes, in particular, the oxidizing deperoxidation of t-butyl and cumyl hydroperoxides in cyclohexane or octane in which the catalyst is a cobalt complex which notably comprises at least one ligand having a bis(2'-pyridylimino)isoindoline skeleton. It is also reported in Example 27 of the '154 application that the compound Co(Oct).sub.2, the structure of which is simpler and which does not include a ligand of the above indicated type, only exhibits very poor efficiency. The '154 application suggests the possible replacement of cobalt, the central metal in the complexes in question, by any other metal of Group VIII, with osmium being one of the possibilities considered. However, the ligands in question are relatively difficult to prepare and the efficiency of the various complexes tested in the reaction under consideration, the principal metal of which being cobalt, remains poor. Development of such technique on an industrial scale is hence also not realistic.